Identification of a mosaic MTOR variant in purified neuronal DNA in a patient with focal cortical dysplasia using a novel depth electrode harvesting technique

OBJECTIVE

Recent studies have identified brain somatic variants as a cause of focal epilepsy. These studies relied on resected tissue from epilepsy surgery, which is not available in most patients. The use of trace tissue adherent to depth electrodes used for stereo electroencephalography (EEG) has been proposed as an alternative but is hampered by the low cell quality and contamination by nonbrain cells. Here, we use our improved depth electrode harvesting technique that purifies neuronal nuclei to achieve molecular diagnosis in a patient with focal cortical dysplasia (FCD).

METHODS

Depth electrode tips were collected, pooled by brain region and seizure onset zone, and nuclei were isolated and sorted using fluorescence-activated nuclei sorting (FANS). Somatic DNA was amplified from neuronal and astrocyte nuclei using primary template amplification followed by exome sequencing of neuronal DNA from the affected pool, unaffected pool, and saliva. The identified variant was validated using droplet digital polymerase chain reaction (PCR).

RESULTS

An 11-year-old male with drug-resistant genetic-structural epilepsy due to left anterior insula FCD had seizures from age 3 years. Stereo EEG confirmed seizure onset in the left anterior insula. The two anterior insula electrodes were combined as the affected pool and three frontal electrodes as the unaffected pool. FANS isolated 140 neuronal nuclei from the affected and 245 neuronal nuclei from the unaffected pool. A novel somatic missense MTOR variant (p.Leu489Met, CADD score 23.7) was identified in the affected neuronal sample. Droplet digital PCR confirmed a mosaic gradient (variant allele frequency = .78% in affected neuronal sample; variant was absent in all other samples).

SIGNIFICANCE

Our findings confirm that harvesting neuronal DNA from depth electrodes followed by molecular analysis to identify brain somatic variants is feasible. Our novel method represents a significant improvement compared to the previous method by focusing the analysis on high-quality cells of the cell type of interest.

Development of an online calculator for the prediction of seizure freedom following pediatric hemispherectomy using the Hemispherectomy Outcome Prediction Scale (HOPS)

OBJECTIVES

Although hemispheric surgeries are among the most effective procedures for drug-resistant epilepsy (DRE) in the pediatric population, there is a large variability in seizure outcomes at the group level. A recently developed HOPS score provides individualized estimation of likelihood of seizure freedom to complement clinical judgement. The objective of this study was to develop a freely accessible online calculator that accurately predicts the probability of seizure freedom for any patient at 1-, 2-, and 5-years post-hemispherectomy.

METHODS

Retrospective data of all pediatric patients with DRE and seizure outcome data from the original Hemispherectomy Outcome Prediction Scale (HOPS) study were included. The primary outcome of interest was time-to-seizure recurrence. A multivariate Cox proportional-hazards regression model was developed to predict the likelihood of post-hemispheric surgery seizure freedom at three time points (1-, 2- and 5- years) based on a combination of variables identified by clinical judgment and inferential statistics predictive of the primary outcome. The final model from this study was encoded in a publicly accessible online calculator on the International Network for Epilepsy Surgery and Treatment (iNEST) website (https://hops-calculator.com/).

RESULTS

The selected variables for inclusion in the final model included the five original HOPS variables (age at seizure onset, etiologic substrate, seizure semiology, prior non-hemispheric resective surgery, and contralateral fluorodeoxyglucose-positron emission tomography [FDG-PET] hypometabolism) and three additional variables (age at surgery, history of infantile spasms, and magnetic resonance imaging [MRI] lesion). Predictors of shorter time-to-seizure recurrence included younger age at seizure onset, prior resective surgery, generalized seizure semiology, FDG-PET hypometabolism contralateral to the side of surgery, contralateral MRI lesion, non-lesional MRI, non-stroke etiologies, and a history of infantile spasms. The area under the curve (AUC) of the final model was 73.0%.

SIGNIFICANCE

Online calculators are useful, cost-free tools that can assist physicians in risk estimation and inform joint decision-making processes with patients and families, potentially leading to greater satisfaction. Although the HOPS data was validated in the original analysis, the authors encourage external validation of this new calculator.

Surgically Remediable Secondary Network Epileptic Encephalopathies With Continuous Spike Wave in Sleep: Lesions May Not Be Visible on Brain Magnetic Resonance Imaging (MRI)

BACKGROUND

Continuous spike wave in sleep (CSWS) is an electroencephalogram (EEG) pattern associated with developmental and epileptic encephalopathy with spike-and-wave activation in sleep (DEE-SWAS). This etiologically heterogeneous syndrome may occur because of genetic factors and congenital or acquired brain lesions. We studied the pattern of clinical presentation and underlying etiologies in patients with DEE-SWAS that respond to resective surgery.

METHODS

We reviewed our clinical and research databases for patients who had resolution of CSWS following surgical resection of a focal lesion.

RESULTS

We identified 5 patients meeting inclusion criteria. In 3 of 5, an epileptogenic structural abnormality was not apparent on brain magnetic resonance imaging (MRI). In all 3 patients, focal cortical dysplasia was identified through intracranial EEG monitoring.

SIGNIFICANCE

DEE-SWAS may be a secondary bilateral network epilepsy syndrome, which can be treated with resection of the inciting focal lesion. In patients with drug-resistant CSWS, clinicians should consider a complete epilepsy presurgical workup, including intracranial EEG monitoring.

RARE-19. Molecular characterization and treatment response of metastatic DIA/DIG

INTRODUCTION: Desmoplastic infantile astrocytoma (DIA) and desmoplastic infantile ganglioglioma (DIG) are glioneuronal tumors of early childhood. Surgical resection is usually sufficient to cure these benign tumors. The presence of metastatic seeding is rare and has been reported as an adverse prognostic factor. We present 2 cases of young children with recurrent metastatic DIA/DIG to describe their presentation, therapeutic management and outcome and to highlight the importance of molecular characterization of these rare tumors to guide adjuvant therapy. CASES DESCRIPTION: The first patient developed metastatic recurrence after initial gross total resection (GTR) of a localized DIG. The disseminated relapse was treated with monthly carboplatin and vincristine (CB/VCR). Complete response was achieved after 15 cycles and the patient has remained in continuous complete remission for 5 years. Post hoc molecular analysis of the tumor revealed a BRAF-RDX fusion. The second patient presented with a disseminated intraventricular relapse following an incomplete resection of a DIA associated with a SPECC1L-NTRK2 fusion. The patient received 2 cycles of CB/VCR with minimal response and was then switched to Larotrectinib leading to a very good partial response (VGPR) 3 months into therapy and has remained on treatment since then with significant clinical improvement. DISCUSSION/ CONCLUSION: In our 2 cases, metastatic recurrence was responsive to adjuvant therapy leading to complete response with conventional chemotherapy in the first one and to VGPR with NTRK inhibitor in the second patient. Early molecular characterization of these benign tumors is critical in case of incomplete resection or metastatic seeding to widen therapeutic options and maximize chance of cure. Response with NTRK inhibitor appears rapid and significant but the total duration of treatment and sustainability of response after discontinuation remain unknown.

Comparison of the real-world effectiveness of vertical versus lateral functional hemispherotomy techniques for pediatric drug-resistant epilepsy: A post hoc analysis of the HOPS study

Objective

This study was undertaken to determine whether the vertical parasagittal approach or the lateral peri‐insular/peri‐Sylvian approach to hemispheric surgery is the superior technique in achieving long‐term seizure freedom.

Methods

We conducted a post hoc subgroup analysis of the HOPS (Hemispheric Surgery Outcome Prediction Scale) study, an international, multicenter, retrospective cohort study that identified predictors of seizure freedom through logistic regression modeling. Only patients undergoing vertical parasagittal, lateral peri‐insular/peri‐Sylvian, or lateral trans‐Sylvian hemispherotomy were included in this post hoc analysis. Differences in seizure freedom rates were assessed using a time‐to‐event method and calculated using the Kaplan–Meier survival method.

Results

Data for 672 participants across 23 centers were collected on the specific hemispherotomy approach. Of these, 72 (10.7%) underwent vertical parasagittal hemispherotomy and 600 (89.3%) underwent lateral peri‐insular/peri‐Sylvian or trans‐Sylvian hemispherotomy. Seizure freedom was obtained in 62.4% (95% confidence interval [CI] = 53.5%–70.2%) of the entire cohort at 10‐year follow‐up. Seizure freedom was 88.8% (95% CI = 78.9%–94.3%) at 1‐year follow‐up and persisted at 85.5% (95% CI = 74.7%–92.0%) across 5‐ and 10‐year follow‐up in the vertical subgroup. In contrast, seizure freedom decreased from 89.2% (95% CI = 86.3%–91.5%) at 1‐year to 72.1% (95% CI = 66.9%–76.7%) at 5‐year to 57.2% (95% CI = 46.6%–66.4%) at 10‐year follow‐up for the lateral subgroup. Log‐rank test found that vertical hemispherotomy was associated with durable seizure‐free progression compared to the lateral approach (p = .01). Patients undergoing the lateral hemispherotomy technique had a shorter time‐to‐seizure recurrence (hazard ratio = 2.56, 95% CI = 1.08–6.04, p = .03) and increased seizure recurrence odds (odds ratio = 3.67, 95% CI = 1.05–12.86, p = .04) compared to those undergoing the vertical hemispherotomy technique.

Significance

This pilot study demonstrated more durable seizure freedom of the vertical technique compared to lateral hemispherotomy techniques. Further studies, such as prospective expertise‐based observational studies or a randomized clinical trial, are required to determine whether a vertical approach to hemispheric surgery provides superior long‐term seizure outcomes.

Hemispherectomy Outcome Prediction Scale: Development and validation of a seizure freedom prediction tool

OBJECTIVE

To develop and validate a model to predict seizure freedom in children undergoing cerebral hemispheric surgery for the treatment of drug-resistant epilepsy.

METHODS

We analyzed 1267 hemispheric surgeries performed in pediatric participants across 32 centers and 12 countries to identify predictors of seizure freedom at 3 months after surgery. A multivariate logistic regression model was developed based on 70% of the dataset (training set) and validated on 30% of the dataset (validation set). Missing data were handled using multiple imputation techniques.

RESULTS

Overall, 817 of 1237 (66%) hemispheric surgeries led to seizure freedom (median follow-up = 24 months), and 1050 of 1237 (85%) were seizure-free at 12 months after surgery. A simple regression model containing age at seizure onset, presence of generalized seizure semiology, presence of contralateral 18-fluoro-2-deoxyglucose-positron emission tomography hypometabolism, etiologic substrate, and previous nonhemispheric resective surgery is predictive of seizure freedom (area under the curve = .72). A Hemispheric Surgery Outcome Prediction Scale (HOPS) score was devised that can be used to predict seizure freedom.

SIGNIFICANCE

Children most likely to benefit from hemispheric surgery can be selected and counseled through the implementation of a scale derived from a multiple regression model. Importantly, children who are unlikely to experience seizure control can be spared from the complications and deficits associated with this surgery. The HOPS score is likely to help physicians in clinical decision-making.

The relationship between Chiari 1.5 malformation and sleep-related breathing disorders on polysomnography

OBJECTIVE

Chiari 1.5 malformation is a subgroup of the Chiari malformation in which tonsillar descent into the foramen magnum is accompanied by brainstem descent. No data exist on whether operative decompression in patients with Chiari 1.5 improves sleep-related breathing disorders (SRBDs) and whether there are radiological parameters predicting improvement.

METHODS

The authors performed a retrospective cohort study of consecutive pediatric patients with Chiari 1.5 malformation and SRBDs at the Alberta Children's Hospital. An SRBD was characterized using nocturnal polysomnography (PSG), specifically with the apnea-hypopnea index (AHI), the obstructive apnea index, and the central apnea index. Preoperative values for each of these indices were compared to those following surgical decompression. The authors also compared preoperative radiographic factors as predictors to both preoperative AHI and the change in AHI with surgery. Radiological factors included tonsillar and obex descent beneath the basion-opisthion line, the presence of syringomyelia, the frontooccipital horn ratio, the pB-C2 line, and the clivoaxial angle.

RESULTS

Seven patients (5 males, 2 females) met inclusion criteria. One patient had two surgical decompressions, each with pre- and postoperative PSG studies (n = 8). The median age was 9 years. Before surgical decompression, 75% underwent tonsillectomy/adenoidectomy. The majority (87.5%) experienced snoring/witnessed apnea preoperatively. The median tonsillar and obex descent values were 21.3 mm and 11.2 mm, respectively. The median values for the pB-C2 line and clivoaxial angle were 5.4 mm (interquartile range [IQR] 4.5 mm, 6.8 mm) and 144° (IQR 139°, 167°), respectively. There was a statistically significant change from preoperative to postoperative AHI (19.7 vs 5.1, p = 0.015) and obstructive apnea index (4.5 vs 1.0, p = 0.01). There was no significant change in the central apnea index with surgery (0.9 vs 0.3, p = 0.12). No radiological factors were statistically significant in predicting preoperative AHI and change in AHI.

CONCLUSIONS

This is the first series of pediatric patients with Chiari 1.5 with SRBDs who demonstrated a marked improvement in their PSG results postdecompression. Sleep apnea has a significant impact on learning and development in children, highlighting the urgency to recognize Chiari 1.5 as a more severe form of the Chiari I malformation.

Outcomes of stereoelectroencephalography exploration at an epilepsy surgery center

OBJECTIVES

Epilepsy surgery is offered in resistant focal epilepsy. Non-invasive investigations like scalp video EEG monitoring (SVEM) help delineate epileptogenic zone. Complex cases may require intracranial video EEG monitoring (IVEM). Stereoelectroencephalography (SEEG)-based intracerebral electrode implantation has better spatial resolution, lower morbidity, better tolerance, and superiority in sampling deep structures. Our objectives were to assess IVEM using SEEG with regard to reasoning behind implantation, course, surgical interventions, and outcomes.

MATERIALS AND METHODS

Seventy-two admissions for SEEG from January 2014 to December 2018 were included in the study. Demographic and clinical data were retrospectively collected.

RESULTS

The cohort comprised of 69 adults of which 34 (47%) had lesional MRI. Reasons for SEEG considering all cases included non-localizing ictal onset (76%), ictal-interictal discordance (21%), discordant semiology (17%), proximity to eloquent cortex (33%), nuclear imaging discordance (34%), and discordance with neuropsychology (19%). Among lesional cases, additional reasons included SVEM discordance (68%) and dual or multiple pathology (47%). Forty-eight patients (67%) were offered resective surgery, and 41 underwent it. Twenty-three (56%) had at least one year post-surgical follow-up of which 14 (61%) had Engels class I outcome. Of the remaining 23 who were continued on medical management, 4 (17%) became seizure-free and 12 (51%) had reduction in seizure frequency.

CONCLUSION

SEEG monitoring is an important and safe tool for presurgical evaluation with good surgical and non-surgical outcomes. Whether seizure freedom following non-surgical management could be related to SEEG implantation, medication change, or natural course needs to be determined.

Long term sequelae of amygdala enlargement in temporal lobe epilepsy

PURPOSE

Amygdala enlargement (AE) has been reported in drug resistant lesional and non-lesional temporal lobe epilepsy (TLE). Its contribution to development of intractability of epilepsy is at best uncertain. Our aim was to study the natural course of AE in a heterogenous group of TLE patients with follow-up imaging and clinical outcomes.

METHODS

A prospective observational study in patients with TLE with imaging features of AE recruited from epilepsy clinics between 1994 and 2018. Demographic data, details of epilepsy syndrome, outcomes and follow up neuroimaging were extracted.

RESULTS

Forty-two patients were recruited including 19 males (45 %). Mean age at onset of epilepsy was 30.6 years and mean duration of epilepsy was 19.9 years. On MRI, 33 patients had isolated unilateral AE and eleven had AE with hippocampal enlargement (HE). Twenty (48 %) underwent temporal resections with most common histopathology being amygdalar gliosis (40 %). Engel Class IA outcome at last follow up (mean, 10 years) was 60 %. Thirty-four patients had neuroimaging follow up of at least 1 year (mean, 5 years). AE resolved in 6, persisted in 25, evolved into bilateral HS in 1, bilateral mesial temporal atrophy in 1 and ipsilateral mesial temporal atrophy in 1. Resolution of AE was associated with better seizure free outcomes (p = 0.013).

CONCLUSIONS

TLE with AE is associated with favourable prognosis yet not benign. Over 50 % were drug resistant and surgical outcomes were similar to mTLE. Resolution of AE on follow up neuroimaging was associated with better seizure free outcomes.

Focal seizures associated with the chapeau de gendarme sign or ictal pouting of insular origin

We report a teenager with childhood onset focal seizures associated with the chapeau de gendarme sign or ictal pouting of anterior insular lobe origin. The chapeau de gendarme sign has been associated with frontal lobe seizures in patients with focal epilepsy. However, in this case, stereo-electroencephalography (SEEG) localized seizures to the anterior insular cortex prior to her typical clinical manifestations. Surgical resection of the insular and frontal-lobe network resulted in seizure freedom. We propose that the anterior insular cortex should be a site of investigation during pre-surgical phase 2 evaluation in patients exhibiting the chapeau de gendarme sign during focal seizures.

•

Chapeau de gendarme seizures or ictal pouting could have insular lobe involvement at electrical seizure onset.

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Phase 2 investigation should include insular monitoring when assessing for this kind of seizures.

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Pediatric population could also have chapeau de gendarme or ictal pouting seizures.

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Ripples were associated with epileptogenicity in insular cortex requiring resection.

Neuromodulation beyond neurostimulation for epilepsy: scope for focused ultrasound

Introduction: Epilepsy is one of the most common neurological disorders and is often difficult to control with medication. Intractable epilepsy often results in compromised quality of life (QOL), neurologic morbidity and even mortality. In carefully selected cases, resective surgery offers the best potential for cure or seizure control. However, a large proportion of patients are not suitable for resective epilepsy surgery. Neuromodulation techniques are increasingly being used to treat such refractory cases. Recently, the FDA approved Magnetic Resonance-guided Focused Ultrasound (MRgFUS) for essential tremor and this novel technology is also being explored in several other neuropsychiatric conditions and neurological disorders, including epilepsy. Area covered: While the literature is scant and scattered, the pertinent literature of the MRgFUS is reviewed with an emphasis on research relevant to its application for epilepsy. Expert opinion: Limited preliminary clinical experiences and research studies with MRgFUS ablation or neuromodulation for epilepsy have shown promising results; however, this procedure remains experimental requiring further investigations. Safe and reversible opening of the blood-brain barrier (BBB) with MRgFUS adds an additional therapeutic avenue by allowing targeted delivery of neurotherapeutics in neurological disorders, potentially including epilepsy. Ongoing clinical trials and research coupled with technological advancements contribute to strengthening the MRgFUS epilepsy field. MRgFUS could be the future technology of choice for 'ablation' or 'sononeuromodulation', and/or a 'targeted therapeutics' for epilepsy.

Evaluation of pediatric glioma outcomes using intraoperative MRI: a multicenter cohort study

BACKGROUND

The use of intraoperative MRI (iMRI) during treatment of gliomas may increase extent of resection (EOR), decrease need for early reoperation, and increase progression-free and overall survival, but has not been fully validated, particularly in the pediatric population.

OBJECTIVE

To assess the accuracy of iMRI to identify residual tumor in pediatric patients with glioma and determine the effect of iMRI on decisions for resection, complication rates, and other outcomes.

METHODS

We retrospectively analyzed a multicenter database of pediatric patients (age ≤ 18 years) who underwent resection of pathologically confirmed gliomas.

RESULTS

We identified 314 patients (mean age 9.7 ± 4.6 years) with mean follow-up of 48.3 ± 33.6 months (range 0.03-182.07 months) who underwent surgery with iMRI. There were 201 (64.0%) WHO grade I tumors, 57 (18.2%) grade II, 24 (7.6%) grade III, 9 (2.9%) grade IV, and 23 (7.3%) not classified. Among 280 patients who underwent resection using iMRI, 131 (46.8%) had some residual tumor and underwent additional resection after the first iMRI. Of the 33 tissue specimens sent for pathological analysis after iMRI, 29 (87.9%) showed positive tumor pathology. Gross total resection was identified in 156 patients (55.7%), but this was limited by 69 (24.6%) patients with unknown EOR.

CONCLUSIONS

Analysis of the largest multicenter database of pediatric gliomas resected using iMRI demonstrated additional tumor resection in a substantial portion of cases. However, determining the impact of iMRI on EOR and outcomes remains challenging because iMRI use varies among providers nationally. Continued refinement of iMRI techniques for use in pediatric patients with glioma may improve outcomes.

Calgary Shunt Protocol, an adaptation of the Hydrocephalus Clinical Research Network shunt protocol, reduces shunt infections in children

OBJECTIVEThe shunt protocol developed by the Hydrocephalus Clinical Research Network (HCRN) was shown to significantly reduce shunt infections in children. However, its effectiveness had not been validated in a non-HCRN, small- to medium-volume pediatric neurosurgery center. The present study evaluated whether the 9-step Calgary Shunt Protocol, closely adapted from the HCRN shunt protocol, reduced shunt infections in children.METHODSThe Calgary Shunt Protocol was prospectively applied at Alberta Children's Hospital from May 23, 2013, to all children undergoing any shunt procedure. The control cohort consisted of children undergoing shunt surgery between January 1, 2009, and the implementation of the Calgary Shunt Protocol. The primary outcome was the strict HCRN definition of shunt infection. Univariate analyses of the protocol, individual elements within, and known confounders were performed using Student t-test for measured variables and chi-square tests for categorical variables. Multivariable logistic regression was performed using stepwise analysis.RESULTSTwo-hundred sixty-eight shunt procedures were performed. The median age of patients was 14 months (IQR 3-61), and 148 (55.2%) were male. There was a significant absolute risk reduction of 10.0% (95% CI 3.9%-15.9%) in shunt infections (12.7% vs 2.7%, p = 0.004) after implementation of the Calgary Shunt Protocol. In univariate analyses, chlorhexidine was associated with fewer shunt infections than iodine-based skin preparation solution (4.1% vs 12.3%, p = 0.02). Waiting ≥ 20 minutes between receiving preoperative antibiotics and skin incision was also associated with a reduction in shunt infection (4.5% vs 14.2%, p = 0.007). In the multivariable analysis, only the overall protocol independently reduced shunt infections (OR 0.19 [95% CI 0.06-0.67], p = 0.009), while age, etiology, procedure type, ventricular catheter type, skin preparation solution, and time from preoperative antibiotics to skin incision were not significant.CONCLUSIONSThis study externally validates the published HCRN protocol for reducing shunt infection in an independent, non-HCRN, and small- to medium-volume pediatric neurosurgery setting. Implementation of the Calgary Shunt Protocol independently reduced shunt infection risk. Chlorhexidine skin preparation and waiting ≥ 20 minutes between administration of preoperative antibiotic and skin incision may have contributed to the protocol's quality improvement success.

Microglia induces Gas1 expression in human brain tumor-initiating cells to reduce tumorigenecity

We reported previously that microglia decreased the growth of human brain tumor-initiating cells (BTICs). Through microarray analyses of BTICs exposed in vitro to microglia, we found the induction of several genes ascribed to have roles in cell cycle arrest, reduced cell proliferation and differentiation. Herein, we tested the hypothesis that one of these genes, growth arrest specific 1 (Gas1), is a novel growth reduction factor that is induced in BTICs by microglia. We found that microglia increased the expression of Gas1 transcript and protein in glioblastoma patient-derived BTIC lines. Using neurosphere assay we show that RNAi-induced reduction of Gas1 expression in BTICs blunted the microglia-mediated BTIC growth reduction. The role of Gas1 in mediating BTIC growth arrest was further validated using orthotopic brain xenografts in mice. When microglia-induced Gas1-expressing BTIC cells (mGas1-BTICs) were implanted intra-cranially in mice, tumor growth was markedly decreased; this was mirrored in the remarkable increase in survival of mGas1-BT025 and mGas1-BT048 implanted mice, compared to mice implanted with non-microglia-exposed BTIC cells. In conclusion, this study has identified Gas1 as a novel factor and mechanism through which microglia arrest the growth of BTICs for anti-tumor property.

Successful treatment of primary intracranial sarcoma with the ICE chemotherapy regimen and focal radiation in children

OBJECT Primary CNS sarcomas are very rare pediatric tumors with no defined standard of care. METHODS This study was a retrospective review of children diagnosed with a primary CNS sarcoma and treated at 2 Canadian tertiary care centers between 1995 and 2012. This report focuses on patients with cerebral hemispheric tumor location due to their specific clinical presentation. RESULTS Fourteen patients with nonmetastatic primary CNS sarcoma were identified; in 9 patients, tumors were located in the cerebral hemisphere and 7 of these patients presented with intratumoral hemorrhage. One infant who died of progressive disease postoperatively before receiving any adjuvant therapy was not included in this study. The final cohort therefore included 8 patients (4 males). Median patient age at diagnosis was 11.8 years (range 5.8-17 years). All tumors were located in the right hemisphere. Duration of symptoms prior to diagnosis was very short with a median of 2 days (range 3-7 days), except for 1 patient. Three (37.5%) patients had an underlying diagnosis of neurofibromatosis Type 1 (NF1). Gross-total resection was achieved in 5 patients. The dose of focal radiation therapy (RT) ranged between 54 Gy and 60 Gy. Concomitant etoposide was administered during RT. ICE (ifosfamide, carboplatin, etoposide) chemotherapy was administered prior to and after RT for a total of 6-8 cycles. Seven of the 8 patients were alive at a median time of 4.9 years (range 1.9-17.9 years) after treatment. CONCLUSIONS In this retrospective series, patients with primary CNS sarcomas located in the cerebral hemisphere most commonly presented with symptomatic acute intratumoral hemorrhage. Patients with NF1 were overrepresented. The combination of adjuvant ICE chemotherapy and focal RT provided encouraging outcomes.

Resective focal epilepsy surgery - Has selection of candidates changed? A systematic review

OBJECTIVE

No standard, widely accepted criteria exist to determine who should be referred for an epilepsy surgical evaluation. As a result, indications for epilepsy surgery evaluation vary significantly between centers. We review the literature to assess what criteria have been used to select patients for resective epilepsy surgery and examine whether these have changed since the publication of the first epilepsy surgery randomized controlled trial in 2001.

METHODS

A systematic review was conducted using PubMed and EMBASE, bibliographies of reviews and book chapters identifying focal epilepsy resective series. Abstract, full text review and data abstraction (i.e. indications for surgery) were performed independently by two reviewers. Descriptive historical analysis was done to examine indications over time.

RESULTS

Out of 5061 articles related to epilepsy surgery, 384 articles met all eligibility criteria. Most common criteria for selecting patients for evaluation for resective surgery were: AED resistance (n=303, most commonly >2 AEDs=46), epilepsy duration (n=53, most commonly >1 year=42) and seizure frequency (most commonly at least one seizure/month, n=29). Out of the prospective studies the most notable change over time (pre-2000 vs. post-2000) was failure of ≥2 AEDs (8% vs. 43% respectively, p<0.001).

CONCLUSIONS

Important variations between studies make it difficult to identify consistent criteria to guide surgical candidacy or changes in indications over time. With increasing evidence that earlier surgery is associated with better outcomes, it is recommended that patients be evaluated as soon as they have failed two AEDs, consistent with the new definition of drug resistant epilepsy. Furthermore, low seizure frequency should not be a barrier to epilepsy surgery. Anyone with drug resistant epilepsy should be promptly evaluated for possible surgery, regardless of seizure frequency.

Pediatric thalamic tumors in the MRI era: a Canadian perspective

BACKGROUND

Thalamic gliomas are rare. The natural history is unpredictable, and the optimal management of these tumors in children is poorly defined. The aim was to identify outcomes, prognostic factors, and response to various modalities of treatment in a relatively large population of pediatric thalamic tumors from many centers within a fairly homogeneous health care system.

METHODS

We performed a Canadian multicenter retrospective review of pediatric thalamic tumors presenting during the MRI era (1989-2012). Radiology and pathology were reviewed by central independent reviewers. Paraffin shavings for RNA extraction were taken and tested for fusion events involving KIAA1549:BRAF. Tumors were classified as unilateral or bithalamic based on their origin on imaging. Univariate and multivariate analyses on factors influencing survival were performed.

RESULTS

Seventy-two thalamic tumors were identified from 11 institutions. Females represented 53% of the study population, and the mean age at presentation was 8.9 years. Sixty-two tumors were unilateral and 10 bithalamic. Unilateral tumors had a greater propensity to grow inferiorly towards the brainstem. These tumors were predominantly low grade in comparison to bithalamic tumors which were high-grade astrocytomas. The 5-year overall survival was 61 ± 13% for unithalamic tumors compared to 37 ± 32% for bithalamic tumors (p = 0.097). Multivariate analysis indicated tumor grade as the only significant prognostic factor for unithalamic tumors. Six unilateral tumors, all low grade, were BRAF fusion positive.

CONCLUSION

Unilateral and bilateral thalamic tumors behave differently. Surgical resection is an appropriate treatment option in unilateral tumors, most of which are low grade, but outcome is not related to extent of resection (EOR). Bilateral thalamic tumors have a poorer prognosis, but the occasional patient does remarkably well. The efficacy of chemotherapy and radiotherapy has not been clearly demonstrated. Novel therapeutic approaches are required to improve the prognosis for malignant unilateral thalamic tumors and bilateral thalamic tumors.

Endoscopic Versus Microsurgical Resection of Third Ventricle Colloid Cysts

Objective:

Endoscopic resection of colloid cysts has been performed as an alternative to microsurgical resection and stereotactic aspiration since 1982. To date, there are limited published studies comparing these procedures. In this study, we present the largest series of endoscopic resections published to date and compare outcomes to a cohort of microsurgical resections performed at the same institution.

Methods:

A retrospective chart review was conducted for all patients in the Calgary Health Region undergoing resection of a colloid cyst between 1991 and 2004. Comparison was made between patients treated with endoscopic resection versus microsurgical resection.

Results:

Twenty-five endoscopic and nine microsurgical procedures were performed. Complete resection was achieved in 24 of 25 procedures in the Endoscopic group, compared with all 9 procedures in the Microsurgical group. Patients in the Endoscopic group had a reduced operative time (mean 104 minutes versus 217 minutes) and reduced length of stay (3.8 days versus 8.4 days) compared to the Microsurgical group. One patient in the Endoscopic group had a complication (hemiparesis/pulmonary embolus). By contrast, 3 patients in the Microsurgical group had complications (seizure, ventriculitis/bone flap infection, and transient memory deficit). There was one recurrence in each group which both occurred at 5 years follow-up. The mean length of follow-up is 38 months in the Endoscopic group and 33 months in the Microsurgical group.

Conclusion:

Endoscopic resection of colloid cysts can be performed with significantly lower risk of complication than microsurgical resection and with equivalent surgical success. Operative time and length of hospital stay are both significantly reduced with endoscopic resection.

Therapeutic activation of macrophages and microglia to suppress brain tumor-initiating cells

Brain tumor initiating cells (BTICs) contribute to the genesis and recurrence of gliomas. We examined whether the microglia and macrophages that are abundant in gliomas alter BTIC growth. We found that microglia derived from non-glioma human subjects markedly mitigated the sphere-forming capacity of glioma patient-derived BTICs in culture by inducing the expression of genes that control cell cycle arrest and differentiation. This sphere-reducing effect was mimicked by macrophages, but not by neurons or astrocytes. Using a drug screen, we validated amphotericin B (AmpB) as an activator of monocytoid cells and found that AmpB enhanced the microglial reduction of BTIC spheres. In mice harboring intracranial mouse or patient-derived BTICs, daily systemic treatment with non-toxic doses of AmpB substantially prolonged life. Notably, microglia and monocytes cultured from glioma patients were inefficient at reducing the sphere-forming capacity of autologous BTICs, but this was rectified by AmpB. These results provide new insights into the treatment of gliomas.

Post-chemotherapy maturation in supratentorial primitive neuroectodermal tumors

Maturation in central nervous system embryonal tumors is an uncommon phenomenon that is mainly reported in the context of specific histological subgroups of medulloblastoma. In this report we describe two cases of histological maturation in patients with supratentorial primitive neuroectodermal tumor with strikingly different outcomes. We discuss the potential impact of such findings on treatment and outcome.

Reduction of microglial activity in a model of multiple sclerosis by dipyridamole

Background

Despite extensive and persistent activation of microglia in multiple sclerosis (MS), microglia inhibitors have not yet been identified for treatment of the disorder. We sought to identify medications already in clinical use that could inhibit the activation of microglia. On the basis of the reported inhibitory effects of dipyridamole on phosphodiesterase activity that result in the production of various anti-inflammatory outcomes, we selected it for study. Dipyridamole is used clinically for secondary prevention in stroke. In this study, dipyridamole was examined using microglia in culture and in the mouse model of MS, experimental autoimmune encephalomyelitis (EAE).

Results

We found that dipyridamole attenuated the elevation of several cytokines and chemokines in human microglia caused by Toll-like receptor stimulation. Morphological characteristics of activated microglia in culture were also normalized by dipyridamole. In mice, dipyridamole decreased the clinical severity of EAE and reduced microglial activity and other histological indices of EAE in the spinal cord.

Conclusions

Dipyridamole is an inhibitor of microglia activation and may have a role in MS and other neurological conditions to attenuate microglial activity.

Memory and health-related quality of life in severe pediatric epilepsy

OBJECTIVES

The purpose of this paper was to investigate the contributions of sociodemographic, neurologic, and neuropsychological variables to health-related quality of life (HRQoL) in children with epilepsy and high seizure burden. Focus was placed on the relationship between memory and HRQoL, which has not been previously investigated.

METHODS

Ninety children with epilepsy receiving clinical care at a tertiary-level children's hospital were retrospectively identified. Primary assessment measures were verbal memory (California Verbal Learning Test-Children's Version) and HRQoL. Other neuropsychological variables included intellectual function, executive function, emotional and behavioral function, and adaptive function. Sociodemographic and neurologic variables were extracted from chart review.

RESULTS

No significant correlations were found between HRQoL and sociodemographic or neurologic variables. Moderate correlations were found between neuropsychological variables and HRQoL. Emotional function (Child Behavior Checklist) and verbal memory (California Verbal Learning Test-Children's Version) emerged as significant predictor variables of HRQoL. Low verbal memory was associated with a twofold risk of low HRQoL, emotional and behavioral difficulty with a 10-fold risk, and the combination of emotional and behavioral difficulty and low verbal memory with a 17-fold risk.

CONCLUSIONS

Verbal memory and emotional and behavioral difficulty are associated with increased risk of low HRQoL, even when other important variables are considered in children with high seizure burden. The results reinforce the importance of neuropsychological assessment in clinical care in pediatric epilepsy and suggest important areas of focus for psychological intervention.

A dialog between glioma and microglia that promotes tumor invasiveness through the CCL2/CCR2/interleukin-6 axis

Glioma cells in situ are surrounded by microglia, suggesting the potential of glioma-microglia interactions to produce various outcomes. As chemokines are important mediators of cell-cell communication, we sought first to identify commonly expressed chemokines in 16 human glioma lines. We found CCL2 (macrophage chemoattractant protein-1) messenger RNA to be expressed by the majority of glioma lines. However, these lines did not express the CCL2 receptor, CCR2, which was found on microglia. Next, we overexpressed CCL2 in the U87 glioma line, which has low basal level of CCL2, to investigate the hypothesis that glioma-secreted CCL2 interacts with microglia to affect glioma growth. Stable clones with 10- to 12-fold elevation of CCL2 have similar growth rate and invasive capacity as vector controls when cultured in isolation. However, in coculture with microglia in a three-dimensional collagen gel matrix, the invasiveness of CCL2-overexpressing clones was increased. Gene array analyses were then undertaken and they revealed that interleukin (IL)-6 was consistently increased in the coculture. Recombinant IL-6 enhanced the invasiveness of glioma cells when these were cultured alone, whereas a neutralizing antibody to IL-6 attenuated the microglia-stimulated glioma invasiveness. Finally, we found that human glioma specimens in situ contained IL-6 immunoreactivity that was expressed on CD68+ cells. This study has uncovered a mechanism by which glioma cells exploit microglia for increased invasiveness. Specifically, glioma-derived CCL2 acts upon CCR2-bearing microglia, which then produces IL-6 to stimulate gliomas. The CCL2/CCR2/IL-6 loop is a potential therapeutic target for the currently incurable malignant gliomas.

MULTIFOCAL COMPLEX GLIONEURONAL TUMOR IN AN ELDERLY MAN

OBJECTIVE

The clinicopathological spectra of a dysembryoplastic neuroepithelial tumor (DNT) and a rosette-forming glioneuronal tumor (RGNT) are expanding. We report here the autopsy findings of a case of complex glioneuronal tumor with combined histological features of both a DNT and an RGNT.

CLINICAL PRESENTATION

A 79-year-old man presented with a 1-month history of confusion and gait difficulties. A magnetic resonance imaging scan revealed obstructive hydrocephalus attributed to a mass in the posterior third ventricle.

INTERVENTION

A third ventriculostomy was performed. Postoperatively, the mass remained unchanged in size for more than 14 months. Thirty-eight months after his initial manifestations, he experienced minor head trauma and was then hospitalized. Despite placement of an external ventricular drain and other supportive treatment, he deteriorated and died. A full autopsy was performed, with emphasis on the brain. The mass lesion and a few independent microfoci situated primarily around the third ventricle showed histological features of pilocytic astrocytoma with recurrent hemorrhage. Far more numerous were microfoci with histological features of a DNT, including floating neurons, as well as typical RGNT-associated, synaptophysin-positive rosettes and perivascular pseudorosettes.

CONCLUSION

The advanced age of the patient, the coexisting histological features of the DNT and RGNT, and the distinctive anatomic distribution of the lesions, being centered on the third ventricle, may lend insight into the histogenetic relationship of a DNT, an RGNT, and mixed glioneuronal tumors.

Epilepsy surgery in the first 3 years of life: a Canadian survey

OBJECTIVE

To determine the clinical characteristics, surgical challenges, and outcome in children younger than 3 years of age undergoing epilepsy surgery in Canada.

METHODS

Retrospective data on patients younger than age 3 years who underwent epilepsy surgery at multiple centers across Canada from January 1987 to September 2005 were collected and analyzed.

RESULTS

There were 116 patients from eight centers. Seizure onset was in the first year of life in 82%, and mean age at first surgery was 15.8 months (1-35 months). Second surgeries were done in 27 patients, and a third surgery in 6. Etiologies were malformations of cortical development (57), tumor (22), Sturge-Weber syndrome (19), infarct (8), and other (10). Surgeries comprised 40 hemispheric operations, 33 cortical resections, 35 lesionectomies, 7 temporal lobectomies, and one callosotomy. There was one surgical mortality. The most common surgical complications (151 operations in 116 patients) were infection (17) and aseptic meningitis in 13. Of 107 patients with seizure outcome assessed more than one year postoperatively, 72 (67.3%) were seizure free (Engel I), 15(14%) had >90% improvement (Engel II), 12 had >50% improvement (Engel III), and 8 did not benefit from surgery (Engel IV). Development improved in 55.3% after surgery.

CONCLUSION

Epilepsy surgery in children younger than 3 years of age is relatively safe and is effective in controlling seizures. Very young age is not a contraindication to surgery in children with refractory epilepsy, and early surgery may impact development positively.

A pediatric experience with endoscopic third ventriculostomy for hydrocephalus

Pediatric neuroscience nurses deal with many children with hydrocephalus. This paper will provide a review of hydrocephalus with a specific focus on third ventriculostomy. Endoscopic third ventriculostomy (ETV) is an accepted treatment option for patients with obstructive hydrocephalus. At the Alberta Children's Hospital in Calgary, Alberta, we have been performing ETV for 15 years. This experience has helped us better understand the complications and benefits of ETV. The author will provide data on the complications specific to ETV in pediatric patients at the Alberta Children's Hospital. A case report comparing neurocognitive testing before and after ETV will be shared. An additional case report of a patient with a spontaneous third ventriculostomy will help illustrate our understanding of the natural history of hydrocephalus.

A first stage genome-wide screen for regions shared identical-by-descent in Hutterite families with multiple sclerosis

The complexity of multiple sclerosis (MS) genetics has made the search for novel genes using traditional sharing methods problematic. In order to minimize the genetic heterogeneity present in the MS population we have screened the Canadian MS population for individuals belonging to the Hutterite Brethren. Seven Hutterites with clinically definite MS were ascertained and are related to a common founder by eight generations. Six of the 7 affected individuals and 21 of their unaffected family members (total = 27) were genotyped for 807 markers. Haplotypes were then inspected for sharing among the six MS patients. There were three haplotypes shared among all six MS patients. The haplotypes were located at 2q34-35, 4q31-32, and 17p13. An additional 15 haplotypes were shared among five of the six Hutterites MS patients. The HLA Class II region was one of the highlighted regions; however, the shared MHC haplotype bore the DRB1*04 allele and not the MS-associated DRB1*15 allele providing further evidence of the complexity of the MHC. Additional genotyping to refine the haplotypes followed by screening for potential variants may lead to the identification of a novel MS susceptibility gene(s) in this unique population.

Metalloproteinases are enriched in microglia compared with leukocytes and they regulate cytokine levels in activated microglia

Microglia are resident immune cells within the central nervous system (CNS). They become activated following neurological insults and increase their expression of cytokines. Also elevated in CNS injuries are proteases, including matrix metalloproteinases (MMPs) and A disintegrin and metalloproteinases (ADAMs). The spectrum of metalloproteinase members expressed by microglia and by the systemic leukocytes that infiltrate the injured CNS is unknown, as are their functions. We determined the levels of transcripts encoding all 24 MMPs, nine ADAMs, and their four physiological antagonists, tissue inhibitor of metalloproteinases (TIMPs), in human microglia, B and T cells, monocytes, and neutrophils. We found a distinct pattern for each immune subset and an enrichment of metalloproteinases in microglia compared with leukocytes. When microglia were activated, there was an upregulation of transcripts for nine metalloproteinases, and reduction of TIMP3. Activation of microglia also resulted in increased levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-10 protein in the conditioned media of cells. The amount of secreted TNF-alpha, but not IL-1beta or IL-10, was suppressed by BB94, a broad spectrum metalloproteinase inhibitor, and by TIMP3 but not TIMP1 or TIMP2. This inhibitory profile suggests the involvement of an ADAM member in TNF-alpha secretion. We conclude that microglia bear a metalloproteinase signature distinct from systemic cells, and that following activation, microglia upregulate TNF-alpha protein levels through a combination of elevated cytokine transcripts, increased metalloproteinase level and activity, and through the decrease of TIMP3. The results have implications for the regulation of neuroinflammation and its outcomes following CNS injuries.

Therapeutic action of cannabinoid on axonal injury induced by peroxynitrite

This study examined whether the potent cannabinoid HU210 ameliorates axonal injury through its indirect action to stimulate the secretion of corticosterone. We observed that HU210 dramatically reduced peroxynitrite-induced axonal injury in rats receiving adrenalectomy and corticosterone replacement treatment. These results suggest that the ameliorating effects of cannabinoids on axonal injury associated with multiple sclerosis are achieved by its direct action, but not by its indirect action to elevate the serum corticosterone levels.

Minocycline attenuates T cell and microglia activity to impair cytokine production in T cell-microglia interaction

Minocycline, a tetracycline with anti-inflammatory properties, has been reported to down-regulate the activity of microglia, whose activation occurs in inflammatory and degenerative diseases of the central nervous system, such as multiple sclerosis and Alzheimer's disease. In these disorders, a T cell component is also evident, and we have demonstrated previously that the interaction of activated T cells with microglia led to the substantial increase in tumor necrosis factor alpha (TNF-alpha) levels. Here, we report that minocycline decreases TNF-alpha levels produced in human T cell-microglia interaction. This effect is mediated by a direct action of minocycline on the activated T cells and on microglia, which resulted in the decreased ability of T cells to contact microglia. In correspondence, minocycline decreased the expression on T cells of the CD40 ligand (CD40L), a key molecule regulating the contact-mediated interaction of T cells with microglia. These results demonstrate that the mechanism of action of minocycline involves not only microglia but also T cells and their subsequent activation of microglia. The capacity of minocycline to down-regulate CD40L on T cells may provide a new means to target the CD40-CD40L pathway, which regulates several inflammatory processes.

Genetic susceptibility to MS: a second stage analysis in Canadian MS families

Four published genome screens have identified a number of markers with increased sharing in multiple sclerosis (MS) families, although none has reached statistical significance. One hundred and five markers previously identified as showing increased sharing in Canadian, British, Finnish, and American genome screens were genotyped in 219 sibling pairs ascertained from the database of the Canadian Collaborative Project on Genetic Susceptibility to MS (CCPGSMS). No markers examined met criteria for significant linkage. Markers located at 5p14 and 17q22 were analyzed in a total of 333 sibling pairs and attained mlod scores of 2.27 and 1.14, respectively. The known HLA Class II DRB1 association with MS was confirmed (P<0.0001). Significant transmission disequilibrium was also observed for D17S789 at 17q22 (P=0.0015). This study highlights the difficulty of searching for genes with only mild-to-moderate effects on susceptibility, although large effects of specific loci may still be present in individual families. Future progress in the genetics of this complex trait may be helped by (1) focussing on more ethnically homogeneous samples, (2) using an increased number of MS families, and (3) using transmission disequilibrium analysis in candidate regions rather than the affected relative pair linkage analysis.

Head injuries in skiers and snowboarders in British Columbia

BACKGROUND

At the Vancouver General Hospital Neurosurgical Service there have been a significant number of seriously brain injured snowboarders, seemingly out of proportion to the number of skiers. The purpose of this study was to determine whether snowboarders suffered more serious head injuries than skiers in the Vancouver catchment area.

METHODS

The British Columbia Trauma Registry was searched for patients incurring head injuries while skiing or snowboarding on British Columbia mountains during the period from January 1992 to December 1997. Patients were included if they were admitted to hospital and underwent neurosurgical consultation.

RESULTS

A total of 40 skiers and 14 snowboarders met the above criteria. Of the skiers, 15% sustained a severe head injury by Glasgow Coma Score, another 30% sustaining moderate head injuries, while 29% of snowboarders had a severe injury and 36% a moderate injury. A concussion was present in 60% of the skiers and 21% of the snowboarders. Snowboarders suffered an intracranial hemorrhage in 71% of the cases compared to 28% of the skiers. A craniotomy was performed acutely in 10% of skiers and in 29% of snowboarders. Three deaths occurred as a direct result of head injury, one while snowboarding. All but one of the surviving skiers were able to return home, whereas four of 13 surviving snowboarders required additional inpatient rehabilitation or transfer to another acute hospital for ongoing care.

CONCLUSIONS

Snowboarders suffer more significant head injuries compared to skiers in this series and are much more likely than skiers to require an intracranial procedure. In our opinion, this indicates that additional safety measures, in particular the use of mandatory helmets, should be considered by ski areas and their patrons.

The natural history of multiple sclerosis: a geographically based study: 8: familial multiple sclerosis

We have examined the demographics and long-term outcome of 1044 patients with sporadic and familial multiple sclerosis in a population-based cohort from London, Ontario. The mean follow-up was 25 years in duration, and by this time most patients had reached the unambiguous endpoint scores of the Kurtzke disability status scale (DSS), DSS 6, 8 or 10. An affected family member was identified in 19.8% of the total population, and this subgroup was further divided arbitrarily into the following three groups by the type and number of relatives affected: (i) first degree only; (ii) first degree plus others; (iii) second or third degree. The outcome in these groups was compared with that for those patients who, at a mean 25 year follow-up, had no relatives known to be affected. Familial cases closely resembled those remaining sporadic in both demographics and outcome, although onset in the most heavily loaded families was earlier and male/female ratio was greater. The times to DSS 6, 8 and 10 did not differ significantly when sporadic, familial and familial subgroups were compared. These results provide no clinical support for viewing familial multiple sclerosis as distinct from the sporadic form. The observed recurrence rate for siblings in a strictly defined epidemiological sample was 3.5%, much as projected. These results validate the recurrence risks which have previously been derived from age-corrected data for these first-degree relatives.

The natural history of multiple sclerosis: a geographically based study. 7. Progressive-relapsing and relapsing-progressive multiple sclerosis: a re-evaluation

Classifications of multiple sclerosis subtypes have been largely based on clinical phenomenology. Nevertheless, definitions of relapse, remission and progression have been imprecise. Recently an international consensus group, as part of a reclassification of disease subtypes, recommended dropping the term 'relapsing-progressive' (RP) and retaining the term 'progressive-relapsing' (PR) multiple sclerosis. The term 'RP' multiple sclerosis had been applied when the early course combined both relapses and progression and was believed to identify some patients with a worse than average outcome. The PR group consisted of patients with primary progressive disease who later in their course developed relapses. Since the terminology has been largely arbitrary, we have evaluated the validity of the terms 'RP' and 'PR' multiple sclerosis in the context of long-term outcome within a large population-based cohort of progressive multiple sclerosis patients seen at the London Multiple Sclerosis Clinic (Canada) between 1972 and 1984. Mean follow-up of the entire cohort was 25 years. Designation of RP multiple sclerosis did identify a more rapidly progressive subgroup. To realign these natural history data with consensus recommendations, these patients were reassigned to secondary progressive (SP) or to primary progressive (PP) multiple sclerosis, with progression defined as at least 1 year of progressive deterioration. PP multiple sclerosis patients with relapses after a year were designated as having PR multiple sclerosis. Relapses in primary progressive multiple sclerosis occurred in 27.8% of patients at some point even two to three decades after onset. In general these relapses were mild and remitting, but served to blur the distinction between progressive and relapsing-remitting disease. The long-term outcomes of time to Kurtzke disability scores (DSS) of 3, 6, 8 and 10 were compared among the progressive subtypes. Times to these disability end-points and to death were not different between PR and PP multiple sclerosis. Survival curves for progressive patients have been amended to incorporate the reassignment of PR multiple sclerosis patients into the PP group and the RP multiple sclerosis patients into the PP and SP subgroups. The time to reach DDS 3, 6, 8 and 10 for a population-based cohort of primary and secondary progressive patients resulting from the elimination of the categories of RP multiple sclerosis and PR multiple sclerosis has been established. These results provide justification for retaining only PP and SP multiple sclerosis as the subgroups of progressive disease.

The natural history of multiple sclerosis: a geographically based study. 5. The clinical features and natural history of primary progressive multiple sclerosis

We report a natural history study of 216 patients with primary progressive (PP)- multiple sclerosis defined by at least 1 year of exacerbation-free progression at onset. This represents 19.8% of a largely population-based patient cohort having a mean longitudinal follow-up of 23 years. This subgroup of PP-multiple sclerosis patients had a mean age of onset of 38.5 years, with females predominating by a ratio of 1.3:1.0. The rate of deterioration from disease onset was substantially more rapid than for relapsing-remitting multiple sclerosis, with a median time to disability status score (DSS) 6 and DSS 8 of 8 and 18 years, respectively. Forty-nine percent of patients were followed through to death. Examination of the early disease course revealed two groups with adverse prognostic profiles. Firstly, a shorter time to reach DSS 3 from onset of PP-multiple sclerosis significantly adversely influenced time to DSS 8. Second, involvement of three or more neurological systems at onset resulted in a median time to DSS 10 of 13.5 years in contrast to PP-multiple sclerosis patients with one system involved at onset where median time to death from multiple sclerosis was 33.2 years. However, age, gender and type of neurological system involved at onset appeared to have little influence on prognosis. Life expectancy, cause of mortality and familial history profile were similar in PP-multiple sclerosis and non-PP-multiple sclerosis (all other multiple sclerosis patients from the total population). From clinical onset, rate of progression was faster in the PP-multiple sclerosis group than in the secondary progressive (SP)-multiple sclerosis group. When the rates of progression from onset of the progressive phase to DSS 6, 8 and 10 were compared, SP-multiple sclerosis had a more rapid progressive phase. A substantial minority (28%) of the PP-multiple sclerosis cohort had a distinct relapse even decades after onset of progressive deterioration. These studies establish natural history outcomes for the subgroup of multiple sclerosis patients with primary progressive disease.

The natural history of multiple sclerosis: a geographically based study. 6. Applications to planning and interpretation of clinical therapeutic trials in primary progressive multiple sclerosis

The natural history of primary progressive multiple sclerosis (PP-multiple sclerosis) recently has been defined in a geographically based multiple sclerosis population. For a series of prognostically defined hypothetical entry criteria based upon current trends in presentation to the London Multiple Sclerosis Clinic, we determined the number of patients who would have been trial eligible. Using 23 year mean longitudinal natural history data, we identified the observed rate of deterioration for frequently used trial endpoints. Hypothetical entry criteria were based on the practical considerations which would attend the execution of clinical trials in progressive multiple sclerosis. We then developed a series of sample size tables giving the number of patients with PP-multiple sclerosis and the length of observation that would be required to detect a significant result (P = 0.05) for a 25, 50 and 75% decrease in the median time to progression with 80 or 90% power, with treatment efficacy based upon the ability to slow progression on the disability status score. It is expected that the considerations outlined here will prove useful for both trial design and interpretation of trials in PP-multiple sclerosis which will require multi-centre collaborative efforts.

A full genome search in multiple sclerosis

The aetiology of multiple sclerosis (MS) is uncertain. There is strong circumstantial evidence to indicate it is an autoimmune complex trait. Risks for first degree relatives are increased some 20 fold over the general population. Twin studies have shown monozygotic concordance rates of 25-30% compared to 4% for dizygotic twins and siblings. Studies of adoptees and half sibs show that familial risk is determined by genes, but environmental factors strongly influence observed geographic differences. Studies of candidate genes have been largely unrewarding. We report a genome search using 257 microsatellite markers with average spacing of 15.2 cM in 100 sibling pairs (Table 1, data set 1 - DS1). A locus of lambda>3 was excluded from 88% of the genome. Five loci with maximum lod scores (MLS) of >1 were identified on chromosomes 2, 3, 5, 11 and X. Two additional data sets containing 44 (Table 1, DS2) and 78 sib pairs (Table 1, DS3) respectively, were used to further evaluate the HLA region on 6p21 and a locus on chromosome 5 with an MLS of 4.24. Markers within 6p21 gave MLS of 0.65 (non-significant, NS). However, D6S461, just outside the HLA region, showed significant evidence for linkage disequilibrium by the transmission disequilibrium test (TDT), in all three data sets (for DS1 chi2 = 10.8, adjusted P < 0.01)(DS2 and DS3 chi2 = 10.9, P < 0.0005), suggesting a modest susceptibility locus in this region. On chromosome 5p results from all three data sets (222 sib pairs) yielded a multipoint MLS of 1.6. The results support genetic epidemiological evidence that several genes interact epistatically to determine heritable susceptibility.

A population-based study of multiple sclerosis in twins: update

This study is a 7.5-year follow-up of a population-based series of twins with multiple sclerosis (MS) whose mean age now exceeds 50 years. The twin pairs were identified through the Canadian nationwide system of MS clinics and were drawn from a population of 5,463 patients. After 7.5 years, the monozygotic concordance rate increased from 25.9 to 30.8% and the dizygotic-like sex concordance rate from 2.4 to 4.7%. These results are very similar to those of other population-based studies and to our own modified replication twin data reported here. We interpret the data to mean that MS susceptibility is genetically influenced, and a single dominant or even a single recessive gene is unlikely to account for this effect. The difference in concordance rates suggests that at least two or more genes are operative. These data also have important implications for the nature of the environmental effect(s) in MS susceptibility. Most monozygotic twins are discordant even after a correction for age and magnetic resonance imaging findings. This unambiguously demonstrates the powerful effect of nonheritable factors.

The influence of pregnancy on disability from multiple sclerosis: a population-based study in Middlesex County, Ontario

We analyzed the effect of pregnancy on long-term disability resulting from multiple sclerosis in 185 women ascertained through a retrospective population-based survey of MS in Middlesex County, Ontario, Canada. There was no association between disability and total number of term pregnancies, timing of pregnancy relative to onset of MS, or either onset or worsening of MS in relation to a pregnancy. The mean number of pregnancies both before and after onset of MS was no different among groups stratified according to disability. This study addresses some of the difficulties inherent in studying the effect of pregnancy on disability resulting from MS.